1. Field of the Invention
The present invention relates to a double cylinder press for the formation of fibrous layers from fiber-containing liquid such as pulp, for example.
2. Description of the Prior Art
A double cylinder press of this type is disclosed in Japanese Patent No. 885078 (Japanese Patent Publication No. 52-10741). The prior art double cylinder press comprises a pair of box-shaped stationary butt and swing butt which are disposed side by side with the opposed sides thereof opened entirely to communicate with each other and which are provided therein one each with cage cylinders covered at the outer circumferences thereof with wire gauzes and rotatably supported by shafts. The swing butt has a construction such that it can longitudinally be swung relative to the stationary butt with a pivot portion formed on the lower portion of the opposed openings as a fulcrum by means of a hydraulic cylinder. The opposed open edges of the two butts, excluding the uppermost open edges, are stretchably joined with each other through a flexible member of rubber cloth, plastic cloth or the like material. With the double cylinder press herein described, fibrous layers of a prescribed thickness can be formed on the surfaces of the respective wire gauzes by longitudinally swinging the swing butt by means of the hydraulic cylinder to thereby adjust the distance between the swing butt and the stationary butt in a region in which the cage cylinders of the two butts are to be brought into pressure contact with each other, then rotating the cage cylinders in prescribed directions, thereby allowing fibers to be extracted from both fiber-containing liquid stored in advance in the butts and fresh fiber-containing liquid supplied from feed pipes and to be adsorbed on the surfaces of the wire gauzes, and causing the fibers on the wire gauzes to butt against each other in the aforementioned region to be compressed and dehydrated.
With the prior art double cylinder press, however, as the stationary butt and swing butt assume a box shape and therefore since the flat shape of the lower portions of the two butts does not match with the circumferential shape of the cage cylinders, fresh fiber-containing liquid, even when supplied continuously to the lower portions of the butts via the feed pipes, is prevented from being guided in the directions of rotation of the cage cylinders and is mixed with the liquid of low fiber contents stored in advance in the butts to be diluted, with the result that the efficiency of adsorption of the fibers in the liquid onto the wire gauzes is considerably lowered.
Since each of the cage cylinders within the butts has its entire length set substantially in the same diameter and is supported by a shaft in a state wherein the opposite end surfaces of the cage cylinder and the corresponding inner wall surfaces of the butt have seal members interposed therebetween, fibers which have peeled off the wire gauzes of the cage cylinders in the course of the formation of the fibrous layers, for example, become a mass having a diameter of about 1 cm and remain above the region in which the cage cylinders come into pressure contact with each other. Since the mass has its escape cut off by the inner wall surfaces of the butts kept in contact with the opposite end surfaces of the cage cylinders and moves above the aforementioned region in a floating state, there is a fair possibility of the surfaces of the wire gauzes being damaged. Further, it is necessary to stop the operation of the apparatus as a whole in removing the mass. Thus, the prior art double cylinder press entails the disadvantages in that the production efficiency is lowered due to the formation of a mass of fibers and that troublesome manual work for removing the mass is inevitably required.
Furthermore, the prior art double cylinder press has a construction such that waste liquid resulting from the compression and dehydration of the fibers by means of the cage cylinders is allowed to drop down through the wire gauzes and discharged out of the apparatus via discharge ports formed in the lower portions of the butts. Actually, however, the waste liquid is not guided downwardly, but is scattered outwardly by the rotation of the cage cylinders to induce a phenomenon of the waste liquid being absorbed again in the fibrous layers once formed. This makes the complete dehydration treatment impossible and results in breakage of the formed fibrous layers.